Thermo-magnetic exchanging device

ABSTRACT

A thermo-magnetic exchanging device includes a heat exchanging element and a magnet unit. The heat exchanging element has at least one channel to convey a heat-carrying fluid. The magnet unit is disposed around the heat exchanging element and provides a magnetic field to the heat exchanging element. The magnitude of the magnetic field is non-uniform. The cross-sectional area of the channel corresponds to the magnetic field so that temperature gradients at different points of the heat exchanging element are substantially the same when the heat-carrying fluid flows through the channel.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The inventions relates to a thermo-magnetic exchanging device, and inparticular, to a thermo-magnetic exchanging device including a heatexchanging element and a magnet unit generating a magnetic field to theheat exchanging element.

2. Description of the Related Art

Magnetic refrigeration is considered a highly efficient andenvironmentally friendly cooling technology. Magnetic refrigerationtechnologies adapt a magnetocaloric effect of magnetocaloric materials(MCM) to realize or utilize refrigeration cycles.

Please refer to FIG. 1, a conventional thermo-magnetic exchanging device1 includes a heat exchanging element 10 and a magnet unit 20. The heatexchanging element 10 includes a channel 11 and a plurality of channels12, wherein the channel 11 is located between the channels 12. In thisembodiment, a heat-carrying fluid flows through the channels 11 and 12,wherein the cross-section areas of the channels 11 and 12 are the same,and the distance between the two adjacent channels 11 and 12 are thesame. The magnet unit 20 can generate a magnetic field to the heatexchanging element 10. Since the magnetic field is non-uniform, themagnetic field in the channel 11 may exceed that in the channel 12, andthe heat exchange efficiency between the heat exchanging element 10 andthe heat-carrying fluid in the channel 11 is greater than that betweenthe heat exchanging element 10 and the heat-carrying fluid in thechannel 12. Thus, the efficiency of the thermo-magnetic exchangingdevice 1 is decreased.

BRIEF SUMMARY OF THE INVENTION

To solve the problems of the prior art, the object of the invention isto provide a thermo-magnetic exchanging device including a heatexchanging element and a magnet unit. The heat exchanging element has atleast one channel. The magnet unit generates a magnetic field to theheat exchanging element. Temperature gradients at different points ofthe heat exchanging element are substantially the same when aheat-carrying fluid flows through the channel.

For the above object, a thereto-magnetic exchanging device includes aheat exchanging element and a magnet unit. The heat exchanging elementhas at least one channel to convey a heat-carrying fluid and has twoends. The magnet unit is disposed around the heat exchanging element andprovides a magnetic field to the heat exchanging element. The magnitudeof the magnetic field is non-uniform. The cross-sectional area of thechannel corresponds to the magnetic field so that temperature gradientsat different points of each end of the heat exchanging element aresubstantially the same when the heat-carrying fluid flows through thechannel

For the above object, a thermo-magnetic exchanging device includes aheat exchanging element and a magnet unit. The heat exchanging elementhas a first channel and a second channel to convey a heat-carryingfluid. The first channel has a first cross-sectional area and the secondchannel has a second cross-sectional area, and the first cross-sectionalarea is greater than the second cross-sectional area. The magnet unit isdisposed around the heat exchanging element and provides a magneticfield to the heat exchanging element. The magnitude of the magneticfield applied to the first channel is greater than the magnitude of themagnetic field applied to the second channel.

For the above object, a thereto-magnetic exchanging device includes aheat exchanging element and a magnet unit. The heat exchanging elementhas a plurality of first channels and at least one second channel toconvey a heat-carrying fluid. The distance between the two adjacentfirst channels is greater than the distance between the two adjacentfirst channel and second channel. The magnet unit is disposed around theheat exchanging element and provides a magnetic field to the heatexchanging element. The magnitude of the magnetic field applied to eachof the first channels is greater than the magnitude of the magneticfield applied to the second channel.

In conclusion, the temperature gradients at different points of the heatexchanging element are substantially the same when the heat-carryingfluid flows through the channel, and the exchange efficiency of thethermo-magnetic exchanging device is increased.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be more fully understood by reading the subsequentdetailed description and examples with references made to theaccompanying drawings, wherein:

FIG. 1 is a schematic view of a conventional thermo-magnetic exchangingdevice;

FIG. 2 is a schematic view of a thermo-magnetic exchanging device of afirst embodiment of the invention;

FIG. 3 is a perspective view of a heat exchanging element of the firstembodiment of the invention;

FIG. 4 is a cross-sectional view along the line A-A′ of FIG. 3;

FIG. 5 is a schematic view of a thermo-magnetic exchanging device of asecond embodiment of the invention; and

FIG. 6 is an exploded schematic view of a thermo-magnetic exchangingdevice of a third embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Please refer to FIGS. 2 to 4. FIG. 2 is a schematic view of athermo-magnetic exchanging device 2 according to a first embodiment ofthe invention. FIG. 3 is a perspective view of a heat exchanging element30 according to the first embodiment of the invention. FIG. 4 is across-sectional view along the line A-A′ of FIG. 3. The thermo-magneticexchanging device 2 includes a heat exchanging element 30 and two magnetunits 40. The heat exchanging element 30 has a tube structure.

The heat exchanging element 30 is made of a material selected from agroup consisting of at least one magnetocaloric material. Themagnetocaloric material, for example, and not limited to, may beMn—Fe—P—As alloy, Mn—Fe—P—Si alloy, Mn—Fe—P—Ge alloy, Mn—As—Sb alloy,Me—Fe—Co—Ge alloy, Mn—Ge—Sb alloy, Mn—Ge—Si alloy, La—Fe—Co—Si alloy,La—Fe—Si—H alloy, La—Na—Mn—O alloy, La—K—Mn—O alloy, La—Ca—Sr—Mn—Oalloy, La—Ca—Pb—Mn—O alloy, La—Ca—Ba—Mn—O alloy, Gd alloy, Gd—Si—Ge,Gd—Yb alloy, Gd—Si—Sb alloy, Gd—Dy—Al—Co alloy, or Ni—Mn—Ga alloy.

The heat exchanging element 30 includes a channel 31 and two channels32. The number Of the channel 31 or the channels 32 is not to belimited. In the embodiment, the channel 31 is located between thechannels 32. The channel 31 and the channels 32 are arranged along afirst extension direction D1. The first extension direction D1 isparallel to a cross-section S1 of the heat exchanging element 30. Theheat exchanging element 30, the channel 31, and the channels 32 areextended along a longitudinal direction D3. The channel 31 and thechannels 32 are provided to convey a heat-carrying fluid.

The magnet unit 40 may be a permanent magnet, a superconducting magnet,or a solenoid. Two magnet units 40 are disposed around the heatexchanging element 30. In the embodiment, the heat exchanging element 30is located between the magnet units 40. The magnet units 40 and the heatexchanging element 30 are arranged along a second extension directionD2, wherein the first extension direction D1, the second extensiondirection D2, and the longitudinal direction D3 are perpendicular toeach other. Each of the magnet units 40 can provide a magnetic field tothe heat exchanging element 30, and the magnitude of the magnetic fieldmay be time-varying and non-uniform. Thus, when the magnetic field isapplied to the heat exchanging element 30, the heat exchange ability ofthe heat exchanging element 30 can be changed.

Please refer to FIG. 2, the cross-section S1 of the heat exchangingelement 30 has a first cross-section zone Z1 and two secondcross-section zones Z2. The channel 31 is located in the firstcross-section zone Z1, and the channels 32 are located in the secondcross-section zone Z2, respectively. The areas of the firstcross-section zone Z1 and the second cross-section zones Z2 are thesame, wherein the first cross-section zone Z1 is located between thesecond cross-section zones Z2. In the embodiment, the firstcross-section zone Z1 and the second cross-section zones Z2 are arrangedalong the first extension direction D1.

The arrangement of the first cross-section zone Z1 and the secondcross-section zones Z2 are substantially parallel to the magnet unit 40.The first cross-section zone Z1 is close to the center area of themagnet unit 40. The second cross-section zones Z2 are close to twoopposite ends of the magnet unit 40. The magnetic field in the firstcross-section zone Z1 exceeds that in each of the second cross-sectionzones Z2. Namely, the magnitude of the magnetic field applied to thefirst channel 31 is greater than the magnitude of the magnetic fieldapplied to each of the second channels 32.

In general, a stronger magnetic field can facilitate higher heatexchange ability of the heat exchanging element 30. Since thecross-sectional area of the channels 31 and 32 are designed tocorrespond to the magnetic field distribution within the heat exchangingelement 30, temperature gradients at different points of thecross-section S1 of the heat exchanging element 30 are substantially thesame when the heat-carrying fluid flows through the channels 31 and 32.

In the embodiment, the cross-section area of the channel 31 is greaterthan the cross-section area of the channel 32, and the area of the firstcross-section zone Z1 and the second cross-section zone Z2 are the same.Since the first cross-section zone Z1 of the heat exchanging element 30has stronger magnetic field, the cross-section area of the channel 31 isdesigned to exceed that of the channel 32.

When the heat-carrying fluid flows through the channel 31 and thechannels 32, the flowing velocity of the heat-carrying fluid in thechannel 31 is higher than that in the channel 32. Since the magneticfield of the second cross-section zones Z2 are lower than that of thefirst cross-section zone Z1, heat exchange ability of the heatexchanging element 30 in the second cross-section zones Z2 arerelatively weak. However, by the slower flowing velocity of theheat-carrying fluid in the channels 32, the heat exchange between theexchanging element 30 in the second cross-section zone Z2 and theheat-carrying fluid in the channels 32 is sufficient. Thus, thetemperature gradients in the second cross-section zone Z1 and the secondcross-section zone Z2 are substantially the same.

Please refer to FIG. 5, which is a schematic view of a thermo-magneticexchanging device 2 a of a second embodiment of the invention. In theembodiment, the heat exchanging element 30 a includes a plurality ofchannels 31 a. The cross-section areas of each of the channels 31 a andthe channels 32 a are the same. However, the number of the channel 31 ain the first cross-section zone Z1 exceeds that of the channel 32 a inthe second cross-section zone Z2. Namely, the total cross-section areaof the channels 31 a in the first cross-section zone Z1 exceeds that ofthe channel 32 a in the second cross-section zone Z2. Moreover, as shownin FIG. 5, the distance between the two adjacent channels 31 a exceedsthat between the two adjacent channel 31 a and channel 32 a. Thus, thetotal cross-section area of the channels 31 a in the first cross-sectionzone Z1 and the total cross-section area of the channel 32 a in thesecond cross-section zone Z2 can be appropriately designed correspondingto the magnitude of the magnetic field.

Please refer to FIG. 6, which is an exploded schematic view of athermo-magnetic exchanging device 2 b of a third embodiment of theinvention. The heat exchanging element 30 b includes a heat exchangingportion 33 and a heat exchanging portion 34, and the heat exchangingportion 33 is coupled with the heat exchanging portion 34. Each of themagnet units 40 b includes a magnet portion 41 and a magnet portion 42,and the magnet portion 41 is coupled with the magnet portion 42. Thechannel 31 includes a channel portion 311 and a channel portion 312.Each of the channels 32 includes a channel portion 321 and a channelportion 322. The channel portion 311 is communicated with the channelportion 312, and the channel portion 321 is communicated with thechannel portion 322.

In the embodiment, the magnetic field generated by the magnet portion 41is greater than the magnetic field generated by the magnet portion 42.The cross-section area of the channel portion 311 exceeds that of thechannel portion 312, and the cross-section area of the channel portion321 exceeds that of the channel portion 322. Thus, the totalcross-section area of the channels 31 and 32 of the heat exchangingportion 33 exceeds that of the channels 31 and 32 of the heat exchangingportion 34. Namely, the cross-sectional areas of the channels 31 and 32can be appropriately designed corresponding to the magnitude of themagnetic field. Thus, when the heat-carrying fluid flows through thechannels 31 and 32, temperature gradients at different points of eachend of the heat exchanging element 30 b are substantially the same.

In conclusion, the temperature gradients at different points of the heatexchanging element are substantially the same when the heat-carryingfluid flows through the channel, and the exchange efficiency of thethermo-magnetic exchanging device is increased.

While the invention has been described by way of example and in terms ofpreferred embodiment, it is to be understood that the invention is notlimited thereto. To the contrary, it is intended to cover variousmodifications and similar arrangements (as would be apparent to thoseskilled in the art). Therefore, the scope of the appended claims shouldbe accorded the broadest interpretation so as to encompass all suchmodifications and similar arrangements.

What is claimed is:
 1. A thermo-magnetic exchanging device, comprising:a heat exchanging element, having at least one channel to convey aheat-carrying fluid and having two ends; and a magnet unit, disposedaround the heat exchanging element and providing a magnetic field to theheat exchanging element, wherein the magnitude of the magnetic field isnon-uniform, wherein the cross-sectional area of the channel correspondsto the magnetic field so that temperature gradients at different pointsof each end of the heat exchanging element are substantially the samewhen the heat-carrying fluid flows through the channel.
 2. Thethermo-magnetic exchanging device as claimed in claim 1, wherein theheat exchanging element is made of a material selected from a groupconsisting of at least one magnetocaloric material.
 3. Thethermo-magnetic exchanging device as claimed in claim 2, wherein themagnetocaloric material is Me—Fe—P—As alloy, Me—Fe—P—Si alloy,Me—Fe—P—Ge alloy, Mn—As—Sb alloy, Me—Fe—Co—Ge alloy, Mn—Ge—Sb alloy,Mn—Ge—Si alloy, La—Fe—Co—Si alloy, La—Fe—Si—H alloy, La—Na—Mn—O alloy,La—K—Mn—O alloy, La—Ca—Sr—Mn—O alloy, La—Ca—Pb—Mn—O alloy, La—Ca—Ba—Mn—Oalloy, Gd alloy, Gd—Si—Ge, Gd—Yb alloy, Gd—Si—Sb alloy, Gd—Dy—Al—Coalloy, or Ni—Mn—Ga alloy.
 4. The thermo-magnetic exchanging device asclaimed in claim 1, wherein the magnet unit is a permanent magnet, asuperconducting magnet, or a solenoid.
 5. A thereto-magnetic exchangingdevice, comprising: a heat exchanging element having a first channel anda second channel to convey a heat-carrying fluid, wherein the firstchannel has a first cross-sectional area and the second channel has asecond cross-sectional area, and the first cross-sectional area isgreater than the second cross-sectional area; and a magnet unit,disposed around the heat exchanging element, providing a magnetic fieldto the heat exchanging element, wherein the magnitude of the magneticfield applied to the first channel is greater than the magnitude of themagnetic field applied to the second channel.
 6. The thermo-magneticexchanging device as claimed in claim 5, wherein the heat exchangingelement is made of a material selected from a group consisting of atleast one magnetocaloric material.
 7. The thermo-magnetic exchangingdevice as claimed in claim 6, wherein the magnetocaloric material isMe—Fe—P—As alloy, Me—Fe—P—Si alloy, Me—Fe—P—Ge alloy, Mn—As—Sb alloy,Me—Fe—Co—Ge alloy, Mn—Ge—Sb alloy, Mn—Ge—Si alloy, La—Fe—Co—Si alloy,La—Fe—Si—H alloy, La—Na—Mn—O alloy, La—K—Mn—O alloy, La—Ca—Sr—Mn—Oalloy, La—Ca—Pb—Mn—O alloy, La—Ca—Ba—Mn—O alloy, Gd alloy, Gd—Si—Ge,Gd—Yb alloy, Gd—Si—Sb alloy, Gd—Dy—Al—Co alloy, or Ni—Mn—Ga alloy. 8.The thermo-magnetic exchanging device as claimed in claim 5, wherein themagnet unit is a permanent magnet, a superconducting magnet, or asolenoid.
 9. A thermo-magnetic exchanging device, comprising: a heatexchanging element having a plurality of first channels and at least onesecond channel to convey a heat-carrying fluid, wherein the distancebetween the two adjacent first channels is greater than the distancebetween the two adjacent first channel and second channel; and a magnetunit, disposed around the heat exchanging element, providing a magneticfield applied to the heat exchanging element, wherein the magnitude ofthe magnetic field applied to each of the first channels is greater thanthe magnitude of the magnetic field applied to the second channel. 10.The thermo-magnetic exchanging device as claimed in claim 9, wherein theheat exchanging element is made of a material selected from a groupconsisting of at least one magnetocaloric material.
 11. Thethermo-magnetic exchanging device as claimed in claim 10, wherein themagnetocaloric material is Me—Fe—P—As alloy, Me—Fe—P—Si alloy,Me—Fe—P—Ge alloy, Mn—As—Sb alloy, Me—Fe—Co—Ge alloy, Mn—Ge—Sb alloy,Mn—Ge—Si alloy, La—Fe—Co—Si alloy, La—Fe—Si—H alloy, La—Na—Mn—O alloy,La—K—Mn—O alloy, La—Ca—Sr—Mn—O alloy, La—Ca—Pb—Mn—O alloy, La—Ca—Ba—Mn—Oalloy, Gd alloy, Gd—Si—Ge, Gd—Yb alloy, Gd—Si—Sb alloy, Gd—Dy—Al—Coalloy, or Ni—Mn—Ga alloy.
 12. The thermo-magnetic exchanging device asclaimed in claim 9, wherein the magnet unit is a permanent magnet, asuperconducting magnet, or a solenoid.